1. Technical Field
Some example embodiments may relate to a fingerprint sensor. More particularly, some example embodiments may relate to a fingerprint sensor having an increased sensing performance.
2. Description of the Related Art
Generally, a fingerprint sensor obtains a fingerprint image of a finger by generating an analog signal having a magnitude proportional to a capacitance between a finger and a sensing electrode included in a pixel, and comparing magnitudes of the analog signals generated by the pixels.
A difference between a capacitance between the finger and a sensing electrode included in a pixel on which a ridge of a fingerprint is located and a capacitance between the finger and a sensing electrode included in a pixel on which a valley of the fingerprint is located is very small. Therefore, a difference between a magnitude of the analog signal generated by the pixel on which a ridge of the fingerprint is located and a magnitude of the analog signal generated by the pixel on which a valley of the fingerprint is located also may be very small.
For this reason, a fingerprint sensor generally performs an integration operation on the analog signal generated by the pixels accumulatively, and obtains the fingerprint image of the finger based on the integrated signal.
As the number of times the integration operation performed on the analog signal increases, a sensing performance may increase. However, as the number of times the integration operation is performed on the analog signal increases, a magnitude of the integrated signal may also increase, thus, a size of an integration circuit may be increased.